Discriminatory antibacterial effects of calix[n] arene capped silver nanoparticles with regard to Gram positive and Gram negative bacteria

Silver nanoparticles capped with nine different sulphonated calix[n] arenes were tested for their anti-bacterial effects against B. subtilis and E. coli at an apparent concentration of 100 nM in calix[n] arene. The results show the para-sulphonato-calix[n] arenes are active against Gram positive bacteria and the derivatives having sulphonate groups at both para and alkyl terminal positions are active against Gram negative bacteria. The calix[6] arene derivative with only O-alkyl sulphonate groups shows bactericidal activity.